Arsenal eventually saw off a stubborn Brighton to move back to the top of the Premier League – where they remained after Liverpool were held to a goalless draw by Manchester United.
The Gunners, now a point clear at the summit, claimed their success thanks to Gabriel Jesus’ header and Kai Havertz’s late strike.
Mikel Arteta’s side dominated the first half against Brighton without reward, but the tension eased when Jesus turned in after a corner.
The hosts were almost punished when Pascal Gross poked a golden chance wide before Havertz sealed victory to spark joyous celebrations at a relieved Emirates Stadium.
The Seagulls, who were looking for a third successive league victory at Emirates Stadium, managed just one shot on target and drop to ninth place.
After a conservative first-half performance, Brighton offered more attacking threat in the final half an hour but anything other than a home win would have been scarcely deserved.
Arsenal had 26 shots in the match and almost added a third in injury-time when substitute Emile Smith Rowe’s low drive was saved.
“It was an incredible performance. It was a joy to watch from the start to the end,” said Arsenal boss Arteta, whose jubilant celebrations indicated the magnitude of the win.
“The way we played against a phenomenal Brighton side was incredible. We were patient, kept going, kept believing and got what we deserved.”
With Liverpool frustrated at home by United, Arsenal now have 39 points from 17 games and next head to Anfield on Saturday for a crucial meeting with Jurgen Klopp’s side.
Arsenal continue to ask questions of Liverpool and Man City
With Liverpool playing later on Sunday, and defending champions Manchester City still behind them after dropping points against Crystal Palace, Arsenal had an opportunity to throw down the gauntlet to their rivals.
Losing a pulsating contest at Aston Villa last weekend had seen the Gunners’ relinquish their spot at the summit and a five-match winning streak in the top flight come to an end.
Nevertheless, the mood in the camp remained upbeat with Arteta and his players stressing the positives from a defeat where they had created enough decent chances to earn something.
Against Brighton, Arteta kept faith with the same starting XI and urged them to make amends in front of their home fans.
The Gunners were unbeaten in 12 home games – since losing 3-0 to Brighton in May – but the first half followed a familiar pattern.
Arsenal moved the ball with pace and purpose against a deep-lying Brighton side, creating several chances for Bukayo Saka, Martin Odegaard, Gabriel and Gabriel Martinelli in a one-sided first half.
However, they were unable to find the ruthless streak which Arteta had demanded.
“I didn’t want to have the feeling of it being another game where we couldn’t score – but you think about it. We had so many chances to put the game to bed,” said Arteta.
Arsenal went into half-time with 15 attempts at goal, of which only three were on target, and the second half started with Odegaard dallying on another chance.
The Gunners’ skipper was guilty of taking too long when presented with the ball in the box, a touch instead of a first-time shot allowing Brighton defender Jan Paul van Hecke to brilliantly nip in.
That inadvertently teed up the opening goal, with Van Hecke flicking the resulting corner on to the far post where Jesus pounced.
Arsenal and their fans knew the importance of scoring a second goal to kill off the game, which was further emphasised when Gross slid wide from a cross which he should have converted.
Eventually the hosts did seal victory when Havertz finished off a slick attacking move with a fourth goal in his past seven games.
Seagulls feed on scraps as scoring streak ends
Brighton are facing a different challenge this season as they juggle domestic and European campaigns with a squad stretched by injury.
Three days after they clinched a place in the Europa League last 16, the Seagulls faced a tight turnaround for one of the toughest trips in the Premier League.
Brighton boss Roberto de Zerbi said they had only one training session to prepare for the game, but refused to look for excuses after a performance where they offered little attacking threat.
Nevertheless, the game would have had a completely different complexion had Gross equalised.
The German perhaps should have slid in with his right leg instead of his left and the miss contributed to Brighton not scoring for the first time in 33 Premier League games.
“I’m disappointed for the result but not for the other things. We deserved to lose. Arsenal played much better than us, they deserved to win the game,” said De Zerbi.
“We had the chance to score in the second half. Maybe it could have been different but we didn’t deserve any points.”